This invention relates to a liquid container and its mouth, and more particularly to a liquid container of bag-in-box type in which a flexible bag for containing a liquid having a high viscosity is accommodated in an outer hard box and a mouth fixed to the liquid container for filling and taking the liquid into and out of the liquid container therethrough. There has appeared a bag-in-box in which a flexible inner bag for containing a liquid such as juice, syrup, beer or ink is accommodated in an outer box made of hard material such as cardboard, plastic and the like. A pump is connected to a mouth of the bag-in-box to take liquid contents out of the flexible inner bag.
However, when the liquid contents are sucked out, the inner flexible bag is deformed to be apt to close the mouth thereof thereby make impossible taking out of liquid contents any more. In the case of liquid having a high viscosity such as ink or adhesive, this phenomenon occurs prominently.
Further, such a bag-in-box is normally set upside down, that is, with the mouth directed downwardly. When the pump is connected to the mouth to such the liquid contents out of the inner bag, a cap fixed to the mouth is disconnected therefrom to expose an inner plug with a membrane for closing the liquid path of the mouth. A connector on the side of the pump is connected to the mouth, and a projection formed in the connector breaks the membrane to open the path for the liquid contents. The structure of the mouth increases its cost because the inner plug and the projection for breaking the membrane of the inner plug are necessary.